You all are familiar with the “Got Plaque? Get a CAC!” screening strategy to identify a “break-in by a cholesterol-laden perpetrator” to your arterial abode. And occasionally people will criticize CACs because they “don’t show soft plaque” and “soft plaque is the vulnerable kind.” No test is perfect, but in an ASYMPTOMATIC PERSON in MIDLIFE, it’s a phenomenal test. Most of the studies (like THIS ONE) where people with CAC=0 ended up having cardiovascular events were in SYMPTOMATIC people with crushing chest pain down their left arms…that’s a different context. It’s important to understand the utility and limitations of each individual biomarker or imaging diagnostic. But hating on CAC is cac-rilegious, especially when there are people insistent on continuing to merely rely on Risk Calculators.
However, this exciting NEW ARTICLE highlights a “CAC 2.0” that may even be superior to the first generation of CAC, particularly in identifying people with CAC=0 who may be at higher risk of cardiovascular events. (This Second Generation CAC will henceforth be referred to as “CAC DeLorean” as an homage to “Back to the Future.” Also, if you were born around the time that classic film was produced, you REALLY need to get a CAC). Using a pretty slick AI-assisted framework to identify smaller, partially calcified lesions that otherwise might be missed, this new method was applied to people with CAC=0 in both the Framingham and MESA cohorts.
And although event rates were quite low (since all these folks had an original CAC of zero), this CAC DeLorean was superior at identifying those who progressed from CAC=0 to CAC>0. But perhaps more importantly, this iteration of CAC better predicted those who experienced cardiovascular events when followed over 20 years. In other words, the 862 people who had a CAC DeLorean>0 were 71% more likely to have an event than those with a next-generation CAC of zero.
To further elaborate, those with a CAC DeLorean of zero had 1.9 events per 1,000 patient years; so if you followed 100 people for 10 years, 2 of those folks might have a cardiovascular event. Conversely, those with the highest levels of CAC DeLorean (who originally were told they had a CAC of zero) had 5.2 events per 1,000 patient years. Still not many more events, but I certainly wouldn’t want to be one of those people that were missed!
This method needs validation across additional cohorts, but maybe this next-generation CAC will prevent additional folks from falling through the CRACKS. And if we successfully identify these people and appropriately intervene, perhaps we can “alter their futures” to be free of cardiovascular events.
